24 hours of Le Mans is a famous endurance race held at a course near Le Mans, France usually in early to mid June. A large number of cars race simultaneously in a number of different classes, the winner being the car that has covered the greatest distance in 24 hours of continuous racing. There are a team of drivers for each car, for a long time two but since the early 1980s three.

The race was first held in 1923 and has only been cancelled in 1936 and 1940-48. The races were originally started with the cars lined up on one side of the track, and the drivers on the other. The drivers then had to run across the track to their cars as the race commenced. Although this practice was discontinued due to its obvious dangers after 1970, it continues to be known as a "Le Mans start". The Le Mans start is also the reason why Porsche street cars continue to have their ignition switches on the left of the steering column rather than the more customary location on the right-- this was easier to reach and enabled the driver to start the car more quickly.

The race is also more sadly known for the worst accident in the history of motor racing. In the 1955 race, a Mercedes being driven in the race by Frenchman Pierre Levegh crashed and went into the crowd, killing the driver and 80 spectators. Mercedes not only withdrew its other cars from the race, it withdrew from motor racing generally as a result, and did not return until 1987. That today's DaimlerChrysler Corporation, owner of the Mercedes marque, is still aware of and sensitive to this incident was evidenced by their re-withdrawal from sportscar racing in 1999 after their CLK sports prototypes caught air and backflipped three times at Le Mans. Aerodynamic modifications intended to prevent recurrence of the problem were implemented after the first incident, but these proved insufficient.

Levegh's accident also prompted the government of Switzerland to ban circuit automobile racing, a ban which still remains in place.

The Le Mans Circuit de la Sarthe itself has undergone many modifications over the years. It is most famous for its long straight, known locally as Ligne Droite des Hunaudières, or more commonly in English as the Mulsanne Straight. By the late 1980s the fastest cars were reaching speeds of approximately 250 mph here, and organizers felt that it had grown unsafe. Two chicanes were consequently put in place in time for the 1990 race to lower speeds. Near the end of this straight is an infamous hump, which gave flight to the Mercedes CLKs mentioned previously. This was flattened out during the winter before the 2001 race, again in the interest of safety. Although some sort of hump remains, it is greatly diminished from what it was.

Other changes have included the replacement of the Maison Blanche ("white house") section with today's Porsche Curves, and the introduction of a new chicane in the Dunlop[?] curve for 2002.

The Le Mans 24 hour race was also famously featured in a movie, titled simply Le Mans, featuring American actor Steve McQueen (who also produced the film), which was released in 1972. This film remains a classic which is still appreciated by racing fans. It was filmed on the circuit using genuine racing cars of the day.

The most successful marque in the history of the 24 hour race is Porsche, with 16 overall victories (including 7 in a row, from 1981 to 1987), followed by Ferrari with 9 (including 6 in a row, from 1960 to 1965). The early years were dominated by Bentley, with 4 consecutive wins from 1927 to 1930.

In a personal spat between the two companies' owners, Ford won the race 4 times (1966-1969) with its GT40, built for the express purpose of defeating Ferrari, after founder Enzo Ferrari backed out of a deal to sell his company to Ford.

The only Japanese company to win the race so far has been Mazda, which won the 59th race in 1991 with its rotary-engined 787B prototype.

2003Bentley won its first Le Mans title since 1930 and Danish driver Tom Kristensen[?] set a record with his fourth straight victory in the 24-hour endurance race. The Bentley team of David Brabham, Mark Blundell and Johnny Herbert finished second.